Phosphate is an essential biologic element; phosphate is required by all cells for normal function and is a critical component of all living organisms. In patient with chronic kidney disease (CKD) stages 2 and 3, the ability to excrete phosphate load is diminished.this work was aiming to detect the early changes occurring in CKD-MBD regarding the urinary phosphorous excretion This is a case-control study applied on 100 subjects admitted to Benha university hospital and Kafr shokr hospital during the period from October 2017 to December 2018.The one hundred subjects were classified into four groups:Those to start with aggregation incorporated twenty five patients with phase 1 CKD. Those second assembly included twenty five patients with phase 2 CKD. The third bunch included twenty five patients with stage 3a CKD. The fourth bunch incorporated twenty five Obviously solid subjects serving Likewise control. Serum phosphorous might have been 3. 39+. 52 On stage1CKD, 3. 45+. 50 On stage2CKD, Furthermore 3. 845 +. 51 On stage3CKD and 24h urinary phosphorous discharge might have been 714. 415+ 171. 49 Previously, stage1CKD, 587. 035+126. 23 to stage2CKD Also 429. 435 +141. 53 done stage3CKD. 24h urinary phosphorous discharge could make used to recognizing which tolerant for punctual phase for CKD with ordinary serum phosphorous level could profit from oral phosphate folio Also cardiovascular intercession done tolerant for CKD.